MALICIOUS
242
Risk Score
Malware Insights
MITRE ATT&CK
T1059.005 Visual Basic
T1105 Ingress Tool Transfer
The file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros are designed to download a payload from the URL 'https://asimmistry.in/ds/121120.gif' and execute it using WinAPI functions like DownloadToFileA and ShellExecuteA. This indicates a downloader or droppper functionality.
Heuristics 5
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Excel 4.0 macro sheet (1 sheet(s)) critical 3 related findings OOXML_XLM_MACROSHEETSpreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
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Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGSExcel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
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XLM payload reassembled from CHAR()/split formulas critical OOXML_XLM_REASSEMBLED_PAYLOADAn Excel 4.0 macro sheet builds its payload inside the formula token stream by concatenating per-character CHAR() calls and string fragments, so no WinAPI name, shell command, or URL is ever contiguous in the .bin for a literal-bytes scan to find. Reassembling the formulas recovered download/execute API names, LOLBin commands (regsvr32/rundll32/mshta/wmic/powershell), or a payload URL — the de-obfuscated download-and-run kill chain.
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URL reconstructed from XLM cell array (1 URL) critical OOXML_XLM_CELL_ARRAY_URLExcel 4.0 macro sheet stages its payload URL across individual numeric cells (one ASCII charcode per cell) or inside an embedded HTA that uses VBScript Chr()/&-concat obfuscation. The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF12 record stream of every worksheet and macrosheet part and decoding RK/inline-string cells in both row-major and column-major order.
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Embedded URL info EMBEDDED_URLOne or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.URL https://asimmistry.in/ds/121120.gif Referenced by macro
Extracted artifacts 1
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
xlm_sheet_00.bine39f99cce4c08293316c530f9ffbec398f6b293f40fe8f01025c72a98bb0721c |
xlm-macrosheet | OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin | 197215 bytes |
Preview scriptFirst 1,000 lines of the extracted script
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% �� & % �� & % �� &
% �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & % �� & ! % �� & " % �� & # % �� & $ % �� & % % �� & & % �� & ' % �� & ( % �� & ) % �� & * % �� & + % �� & , % �� & - % �� & . % �� & / % �� & 0 % �� & 1 % �� & 2 % �� &
... (truncated)
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